Others have sought to address the off-alignment bolt carrier problem associated with many rifle designs. (See http://heavybuffers.com/anticant.html) The applicant inventor knows of no one, though, who provides for the self-centering alignment system of a buffer assembly and spring-loaded carrier insert that work together to align the bolt carrier assembly during the firing sequence. There is no known system that puts the elements of the buffer assembly and the bolt carrier assembly into a cooperative relationship to improve alignment while providing “slack” in the system. That “slack” is necessitated by the number of the manufacturers who produce parts for weapons like the AR15/M4 inasmuch as such manufacturers may various have parts of different sources in the same rifle. Some manufacturers have attempted to solve the carrier tilt issue by adding more material to the bolt carrier with proprietary designs. Others have attempted to address the slop of the upper and lower receivers with a plastic spacer placed between the upper and lower members but such spacers can easily become dislodged, damaged or lost.
The spring-loaded ball bearing carrier insert assembly fits known conventional equipment manufacturer carriers. The carrier insert has a corresponding buffer assembly machined with an alignment concavity or dimple which aligns the carrier. The effective joining of the buffer assembly and the bolt carrier assembly allows for the receiver lower and receiver upper to be fit tighter and the bolt to stay aligned much better. The buffer locking system allows the bolt carrier constantly to be under forward pressure to assure the bolt is in the closed position and will therefore fire safely and more reliably over the life of the rifle.
In testing, applicant has found the buffer locking system invention embodying the present invention to keep the bolt carrier assembly aligned for better reliability and even wear on the bolt head, extractor and barrel extension, and for less part fatigue and wear. Also the structure disclosed in the present application keeps constant light pressure on the bolt carrier assembly ensuring better bolt lock for enhanced reliability especially even under fouled and dirty rifle conditions. Moreover, the system reduces “bolt carrier tilt” seen in many piston designs, allowing for less wear on the buffer tube and less friction that could cause reliability issues. The system lowers the chance of “bolt bounce” because of the constant forward pressure on the bolt carrier assembly thereby providing enhanced reliability. The system enhances bolt carrier assembly alignment, thereby providing a better ejection pattern. The system improves the fit of the receiver upper and receiver lower. The present system is composed of drop-in parts where, even if the carrier insert were lost, the rifle would still function.